The invention relates to a bearing for toothed wheels.
In transmission having helical gears the toothed wheels are loaded by an axial force generated by the helical gears. Especially in transmissions having several countershafts for load distribution, in the toothed wheel of the second constant which is mounted in the area between the input shaft and a main shaft supported in or upon the input shaft, there arises in different load conditions the problem that the bearing of the toothed wheels is deformed by the axial forces. The toothed wheels mounted with some play on the input shaft or the main shaft in transmissions, having several identical countershafts for load distribution, are radially supported in the toothed wheels mounted on the countershafts, but they require an axial bearing so that they do not leave their axial position on the respective shaft. However, the axial forces from the helical gears try axially to move the position of the toothed wheel.
Essentially three operating conditions are distinguished:
In the first uncritical operating condition, the torque is transmitted by the input shaft of the transmission to the countershaft via the toothed wheel of the first constant. The axial bearing is loaded with relative uniformity.
The axial forces have an especially negative effect in the other two operating conditions. On one hand, this is the operating condition in which the torque flow is transmitted by the input shaft of the transmission to the countershafts via the toothed wheel of the second constant. From there, the torque is then transmitted to any toothed wheel connectable with the main shaft. The second problematic operating condition is reached when, to form a ratio step, the input shaft is connected with the main shaft, via the toothed wheels of the first and second constants, and the torque flows, via the toothed wheels of the two constants. The axial force appearing in the first operating condition tries axially to move the toothed wheel of the second constant in a direction away from the input shaft. The axial force appearing in the second operating condition, tries axially to move the toothed wheel of the second constant in a direction toward the input shaft. In both cases, the axial forces lead to a slanted position of the axial bearing of the toothed wheel of the second constant.
DE 196 33 281 has disclosed an axial bearing for the toothed wheel of the second constant. The plate used there is laterally enclosed by two roller bearings. The axial forces lead to a slanted position for the plate and this results in damage to the roller bearings in the form of edge brackets with the consequence of a clearly reduced service life of the bearings.
The problem on which the invention is based is to indicate a bearing which overcomes the problems of the slanted position for the roller bearings.
According to the invention, in a toothed wheel of a gear transmission, in the area between a first shaft and a second shaft, particularly between the input shaft and the main shaft of the transmission, which can rotate substantially coaxially at different rotational speeds relative to each other, the toothed wheel is mounted upon means, especially a plate between a first and a second axial bearing, and to compensate for axial forces in direction of the axis of rotation of the shafts, between the first shaft and the first axial bearing and between the second axial bearing an the second shaft, respectively, is provided one plate which contacts the relevant shaft in one line and with which conical deforming movements can be effected around the line. By conical deforming movement is to be understood that the flat plate undergoes, by the action for the axial force, a deformation to a tapered annular plate which lends it an outline similar to a plate spring.
In an advantageous development contact area, provided with a radius, are formed which make the linear contact possible between the plate and the shaft. The contact areas can be formed directly on the shaft or advantageously be provided at least partly on a part connected with a shaft. The radius of the contact areas and the thickness of the plate can be advantageously adapted to the axial forces that appear.
With the inventive bearing, the slanted position resulting from the axial forces, especially from the helical gears of the toothed wheels, can be detected and kept away by the axial bearings, especially the roller bearings between the shafts.